Stabilized organic compositions containing alkylated bisphenyl compounds



2,745,726 Patented May 15, 1956 STABILIZED ORGANIC COMPOSITIONS CONTAIN- ING ALKYLATED BISPHENYL COMPOUNDS David W. Young and George E. Serniuk, Roselle, and Delmer L. Cottle, Highland Park, N. 1., assignors to Esso Research and Engineering Company, a corpora tion of Delaware No Drawing. Application February 17, 1951, Serial No. 211,582

9 Claims. (Cl. 44-78) This invention relates to the stabilization of organic compounds which tend to deteriorate in storage or in use due to undesirable oxidation reactions. In accordance with this invention, these organic compounds are stabilized against oxidation by incorporating therein small amounts of novel alkylated bisphenyl derivatives, i. e., alkylated bisphenols and alkylated (4-hydroxy-4'-methoxy) diphenyl alkanes.

Various organic compounds and mixtures, including mineral oils, resins, insecticides, soaps, lubricating oils, waxes, rubbers, polyolefins, such as polyisobutylene, etc., are adversely affected by oxygen, with the resultant formation of undesirable oxidation products, breakdown products, gums and usually discoloration of the organic compounds as well as other deleterious reactions.

Thus, for example, in the oil refining industry, in order to prepare lubricating oils of superior quality, it is generally necessary to stabilize the oil against degradation which normally occurs due to oxidation of the hydrocarbon components. In general, hydrocarbon mixtures falling in the lubricating oil boiling range, if unstabllized, will, over a period of time under certain conditions, be subject to gum formation, sludge formation, the formation of acids and the formation of objectionable color bodies.

It is also known that synthetic rubbers undergo changes due to further polymerization or degradation due to depolymerization on exposure to air and consequently yield on vulcanization inferior products unless there is incorporated therewith at time of synthesis 21 compound which stabilizes the synthetic rubber by largely preventing oxidation, degradation and/or cyclization of the chain molecules present in the polymer structure. Natural, as well as synthetic, rubbers require an anti-oxidant present in the vulcanizate in order that finished rubber products remain stable toward oxidation and heat during their useful life.

Bisphenols such as 2,2-di-(p-hydroxyphenyl) propane, hereafter referred to simply as diphenylol propane, have been tried previously as anti-oxidants for various hydrocarbon materials such as wax, natural rubber and hydrocarbon polymers of other kinds. However, these compounds proved to be generally inferior to other types of known anti-oxidants and for this reason, their use as antioxidants never was commercially adopted by the art. The major difiiculty in the use of conventional bisphenols as anti-oxidants has resided in their excessive polarity and consequently limited hydrocarbon solubility and excessive water solubility. The latter characteristic resulted in the bisphenols being lost due to leaching in the presence of water.

It has now been found that particular alkylated bisphenol-type compounds are extremely effective oxidation inhibitors and stabilizers for materials which usually degrade in the presence of air and/ or heat. In addition, the compounds of this invention do not sufier from the above-listed disadvantages of the simple bisphenols.

The compounds utilized for the anti-oxidant purposes of this invention are thus largely water-insoluble and oil-soluble, a desirable combination of characteristics.

These compounds, which are believed to be new chemicals and are solid in nature, are thus illustrated in Formula I below:

wherein R is a radical selected from the group consisting of hydrogen and alkyl radicals having from 1 to 5 carbon atoms, and the R' symbols represent alkyl radicals having 4 to 22 carbon atoms where the several R radicals H3 can be the same or different.

It is diflicult to ascertain the exact linkage of the R' groups to the aromatic nuclei, but because of the orientation eltect of the hydroxyl and OR group, the R' groups are believed to be positioned ortho to these latter radicals, or possessed of the following structure:

It is preferable to have the latter structure. Particularly efiective and desirable compounds of the class of compounds of this invention are 2,2 bis(4-hydroxy,3,5 di t-butyl phenyl) propane and 2,2-(4-methoxy-4'-hydroxy)3',5' di t-butyl diphenyl propane.

It should be noted that the alkoxy or OH group of the alkylated phenyl group occurs para to the alkane linkage. It is this configuration which is believed to impart the desired characteristics to the products of this invention.

In general, the compounds of this invention can be prepared by various procedures starting with the indicated bisphenols. These latter compounds are first prepared by condensing in a known manner two moles of a simple or a chlorine-substituted phenol with one mole of a ketone or aldehyde such as acetone, formaldehyde, methyl ethyl ketone, methyl n-butyl ketone or methyl isobutyl ketone. If the (4-hydroxy-4-methoxy) diphenyl alkane is to be alkylated, it is first prepared by methods such as by reacting diphenylol propane under heat and pressure with methyl chloride and/or methyl iodide in the presence of compounds like postassium hydroxide and methyl alcohol.

The bisphenyl derivative can be alkylated by several methods. One of the preferred methods involves the use of alkyl halides as the alkylating agent in an excess of the alkyl halide as a solvent. In this method bisphenols may be alkylated'with alkyl halides, preferably those of four to ten carbon atoms, in the presence of l to 5 wt. percent of aluminum chloride. The temperature of 'alkylation is about 30 to C. and the time of reaction is from about 1 to 8 hours. Auxiliary solvents such as nitromethane, nitrobenzene, tetrachloroethylene, etc., may be employed. The substituted bisphenyl derivatives may also be alkylated with various olefins, e. g., isobutylene, propylene, amylene, diisobutylene, polypropylene, etc., utilizing catalysts such as BF3 ether, H2804, AlCls, sulfonic acids, etc., under dry conditions, with agitation, and a temperature of about 50-60 C. with a concentration of catalyst of about 0.1 to 2% by weight, to produce the mono, di, tri and tertiary alkylated products.

The following examples are given to illustrate this invention and include both the preparation of the products of this invention and test results on their use as anti-oxidants.

EXAMPLE I Preparation of diphenylol propane olkylated with 2 moles of t-bzt'tyl chloride One mole of finely powdered diphenylol propane was placed in a three-necked R. B. Pyrex flask fitted with a reflux condenser and agitator. Tothis product was added 2 moles of dry t-butyl chloride that contained 5 grams .of anhydrous. AlCl3.- The mixture was agitated for 5 hours at the B. P. of the t-butyl chloride. HCl was liberated by this alkylation reaction. The product was well washed with water and then dried. A product, 84%' yield based on reactants, distilled predominantly at 219" C. at 4 mm. Hg. This product showed the following analysis? 80.81% carbon, 9.65% hydrogen. It had a meltingpoint of 32 C. and'a molecular weight of 324. The product was apparently t'ert-butyl tert-butyl As calculations indicate, this compound has the following characteristics: a

81.18% carbon 7 9.41% hydrogen 340 molecular weight EXAMPLE H 1 Preparation of diphenylol propane alkylated with 4 moles of t-butyl chloride I One mole of diphenylol propane was alkylated with 4 moles of t-butyl chloride. The alkylation conditions were the same as that given in Example I. Under these conditions the product was obtained 88% yield. It distilled predominantly at 254 C. at 4 mm. Hg. The molecular weight of the product was 454.

I EXAMPLE HI Preparation of 2,2-(4-methoxy-4-hydroxy) diphenyl pro-' 50 pane alkylated with 4 moles of isobutylene One mole of 2,2-. (4-rnethoxy 4'-hydroxy) diphenyl propane was alkylated with 4 moles of iso'b'utylene in the presence of 98% H2SO4 catalyst. To make 2,2-(4-methoxy-4--hydroxy) diphenyl propane, one mole of di phenylolf propane was heated in a'steel bomb with one mole of methyl chloride. The solvent for the reac= tion was one mole of CHsOH and the catalyst was one mole of KOH. The time of reaction was three. hours and the temperature was 350 0. The reactants were "diluted with 2 moles'of heptane-" water washed, dry, catalyst-free product, which distilled predominantly at 260 C. at 4 mm. Hg, was 88%.

' EXAMPLE'IV Preparation of diphenylol proponeplkylated with 4 moles of rr-decyl bromide One mole of diphenylol propane was dissolved in 3'50 grams of hot nitromethane. To this solution was added 5 grams of A1013. About 5 minutes after the catalyst had been added, 4 moles of n-decyl bromide was added.

The alkylation was conducted for 10 hours at the boiling point of the mixture under reflux. After this, the alkylated product was well washed with water, 5% NaHCOa and then water. Upon drying, allot the product was soluble in mineral oil. This solubility test proved that diphenylol propane was not present in the final product- The yield of soluble-product was very highover 97.5% of theory and no insoluble material could be detected.

Y EMMPLE V In this example the testused to evaluate the products claimed in this invention was the AST M Oxidation Stability Test designated as ASTM-D-525-46. Essentially, this test consists of placing cc; of the composition in a bomb, after which oxygen is added to provide a pressure of about 100 lbs. p. s. i; 5;. The bomb is then heated to about 100 C. and the pressure in the bomb determined at 15-minute intervals. When sufficient time has passed so that the pressure drops two lbs. pi s. i. g. in 15 minutes, the test is discontinued and the time required to reach this condition is recorded at the induction period or the ASTM breakdown time and is ordinarily given in minutes. A material subjected to this testwhich is markedly unstable to oxidationwill result in an ASTM breakdown time of about one hour, while an oxidation stable mixture will be characterized by breakdown times of 150 minutes or longer. In the data presented below, 2 lbs.

2,2-(4-meth0xy-4-hydr0xy) 3,5 di t butyl diphenyl propane These data prove the excellent anti-oxidant efiect of the compounds of this invention. It should be particularly noted that an improvement of 125% was obtained when the alkylated compounds of this invention were used as compared to the non-alkylatedpredecessor compounds.

EXAMPLE yr The products of this invention were tested for antioxidant effectiveness on a rubber-like polymer of a monoolefin known as Vistanex. The results, including control results, are given below and indicate clearly the excellent anti-oxidant effect of the compounds of this invention,0.25 wt. percent of anti-oxidant being employed where indicated} The Vistanex, in the form of small pieces, was held on a watch glass in a dark air-circulated oven.

M. Wt. of

- Original Vistanex Percent Anti-oxidant. M. Wt. of After 6 Vistanex Weeks at 0.25 Wt. percent 2,2 bis(4-hydroxy, 5 di t-butyl phenyl propane 1 92, 000 84, 000

The yield of final 7 EXAMPLE VII Some of the productsof this invention were evaluated on the ASTM test'on diisobutylene. The results follow:

' A t Ant' 15 menu 0 1- rea Name of Anti-oxidant oxidant down Min.

Blank NonemQ. 2,6 'di t-"butyl ii-methyl phenol 1 1b. per'5,000 gal Y 580 2,2 bis(4-hydroxy, 3,5 di t-butyl 1 lb. per 5,000 gal j 690 phenyl) propane.

This test'shows an almost seven-fold increase on breakdown time through the use of the compounds of this invention and that they were more efiective than 2,6 di t-butyl 4-methyl phenol, one of the best known antiacrylate, styrene, alpha methyl styrene, vinyl naphthalene, vinyl ketones, vinylidene chloride, diethyl fumarate, vinyl pyridine, and the like. Vulcanized natural rubber is also stabilized by the compounds of this invention.

oxidants that has been approved for use in aviation 5 The incorporation of the alkylated compounds with gasoline by the U. S. Army and Navy. the synthetic rubber may be carried out simply by adding EXAMPLE VIII the compounds either in the pure form or in solution, The products of this invention were evaluated as antisusp 61.185011 or emulsiop to a Waite}- dispers.i(m or a latex oxidants in a mineral oil (41 S S U at 210 F and 112 wntgmmg the sytithetlc. rubber dlsgersed an aqueinls V I) The Insults follow mediunrsuc h as is ordinarily obtained by an emulsion polymerization process, or they may added during the milling operation, which is the more convenient way in Sample fif f fi case of natural rubber and GR-I.

oxidant Hrs. The Vistanex (polyisobutylene synthetic rubber) compositions stabilized by the product of this invention have U- Y Y 19 M 420 a Staudinger molecular weight of 40,000 to 300,000. 3135i:23553215123 i ifigigiiigig$535332: 81 i5 233 Mixtures of the compounds of this invention may be employed as well as the P285, chlorine, sulfur, barium, 1H. Staeger test-Chemlsches Zentralblatt, Part I, vol. 100, p. 594 etc., derivatives. Styrene aralkylated compounds, as (1929) 20 well as the alkylated compounds, can be employed. 'lhese results indicate that the compounds of this inven- The amount of the indicated ingredients added to the non are about as good or better than 1 t'butyl normally oxidizable material in order to prevent oxida- 4-methyl phenol, one of the best known anti-oxidants. fion varies with different materials EXAMP E X In general, the amount that has to be added to the The product of Example IV was blended in a Pennsylnormally oxidizable material represents only a small vania neutral oil. The results are listed below: proportion of the normally oxidizable substance, i. e.,

Kin. Vis. Pm. Nam. 3 ,5,35- v. I. ite? Penn. Neut +32 29.8 4.99 42. 57 101 130 Penn. Neut.+1% of n- Decyl Bromide Alkylated diphenylol propane 5 +32 29.7 4.98 42.56 101 210 Penn. Neut.+2.5% n- Decyl Bromide Alkylated diphenylol propane 15 +32 225 1 Not determined.

These results indicate that the compounds of this in- 0.0003-5 wt. per cent based on the normally oxidizable vention, in addition to improving the heat stability of the material. oil, also reduce the pour point, a desirable combination Typical formulations are as follows with the weight of characteristics. per cent figure based on the normally oxidizable It is to be seen from the above examples that the com substance: pounds of this invention provide markedly effective oxidation inhibition. As a result of these tests, it is contem- Gasoline 5 prestint per 5000 Plated in accordance with this invention that the class 826 3: of inhibitors indicated can be used to stabilize oxidation cent) p unstable mixtures. These alkylated bisphenols are par- Lubricating oils 0.02t010% by weight. ticularly adapted for use with synthetic ester lubes, mm- Rubbers and lastics 0 1 to 57 b ht eral oils, greases formed from metallic soaps and esters, h p d 'f; 0 yw 1g rubbers, and wax-polymer blends. T e compoun s o t is invention may be utilized in It is also proposed that the alkylated anti-oxidants of conjunction with other anti-oxidants in order to obtain this invention be employed particularly to stabilize the desirable1 combinatioiis of properties. Among the other class of oils known as turbine oils. 'Iurbine oils are aHt Xi ant materias Which may be so employed are highly refined lubricating oils having a range in Saybolt pheiilyl-ti p y and other aromatic amines, viscosity at 210 F., from about 43 to 145 to whi h are nap the s, substituted naphthols, substituted phenols, added suitable anti-oxidants, rust preventers, pour de- 60 substituted catechols, substituted hydroquinones, alkyl pressants, V. I. improvers, and other additives. phenol sulfides, ketone-amine condensation products and The synthetic rubbers which may be stabilized in ac- 1ike- D118 to i fact tlat compounds have good cordance with this invention in addition to GR-I (iso- 00 y y miXe Wit fi- Y- Y butylenediolefin polymer) rubber are the polymers con- 65 y Phenol n rubber r re n Compounds to form sistint ig predominantly ofb a polymerizablle egonjudgated g l t l l g a id f th t h diole n having 4 to 6 car on atoms, e. g., ,3- uta iene, c an -0Xi an compoun s 0 1s lnven ion ave i o ren 2,3-dimethy1butadiene, zhio -lj-bntadi many advantages among which are their extreme potency, piperylene, 2-methyl-l,3-pentadiene and the like; hence, ease of preparation, good color retention, non-staining synthetic rubbers of the above class include polymers of and odorless character, solubility in hydrocarbons and these materials and also eopolymers prepared by the insolubility in water. I polymerizaticfm ofhmonolmer mixltaiiireglcengprisigg it major lth 18 to understolod tlilat 1th}: lnveantion no; limiteld proportion o sue a po ymeriza e 'o e 11 an a so 0011- to t e specl c examp es w ic ave een o ere mere y taining a minor proportion of other monoethylenically as illustrations, since other derivatives can be prepared, unsaturated compounds copolymerizable with the diolefin and that modifications may be made without departing such as acrylonitrile, methyl acrylonitrile, methyl methfrom the spirit of the invention.

7 c What is claimed is: 1. As new chemicals, hydrocarbon oil-soluble alkylated bisphenyl type compounds corresponding to the general formula 7 RI! RI! I t R in, r R

wherein each of the four R radicals is an alkyl group having 4 to 22 carbon atoms.

"3. A bisphenyl compound according to claim 2 wherein all fourvR" radicals are tertiary butyl groups.

4. A composition of matter comprising an organic hydrocarbon material normally subject to oxidative changes containing a minor proportion in an amount of 0.0003-5 Weight per cent basedon the normally oxidizable material efiective' as an anti-oxidant of a hydrocarbon oil-soluble bisphenyl type compound corresponding to the general formula 6. A composition as in claim 4 wherein the oxidizable organichydrocarbon material is a turbine oil.

7. A cracked gasoline composition containing as an ,8" inhibitor against oxidative deterioration an oil-soluble bisphenol compound corresponding to the formula RI! wherein R is a radical selected from the group consisting of hydrogen and alkyl radicals having 1 to 5 carbon atoms, and R is an alkyl radical having 4 to 10 carbon atoms, the bisphenol' compound being present in an amountcorresponding to about 0.001 to 5 lbs. per

5,000 gallons of gasoline.

8. A cracked gasoline composition containing-as an inhibitor against oxidative deterioration an oil-soluble bisphenol compound corresponding to the formula RI] RI! OH; R. wherein R" is an alkylradical having 4 to 10 carbon atoms, the bisphenol compound being present in an amount corresponding to about 0.001 to 5 lbs. per 5,000 gallons of gasoline.

9. A gasoline composition as in claim 8 wherein all four R" radicals of the bisphenol compound are tertiary butyl groups.

7 References Cited in the file of this patent UNITED STATES PATENTS 1,788,529 Koenigsberger Jan. 13, 1931 1,972,599 Perkins et a1. Sept. 4, 1936 2,061,779 Semon Nov. 24, 1936 2,248,831 Stillson et al. July 8, 1941 2,482,748 Dietzler Sept. 27, 1949 2,504,064 Bock et a1. Apr. 11, 1950 2,504,382 Bousquet et al. Apr. 18, 1950 2,515,906 Stevens et a1 July 18, 1950 2,515,907 Stevens July 18, 1950 2,515,908 Stevens July 18, 1950 2,535,015 Johnson et a1 Dec. 19, 1950 2,542,972 Thompson Feb. 27, 1951 FOREIGN PATENTS 497,039 1950 Belgium Aug. 14,

Qi TQ 

1. AS NEW CHEMICALS, HYDROCARBON OIL-SOLUBLE ALKYLATED BISPHENYL TYPE COMPOUNDS CORRESPONDING TO THE GENERAL FORMULA 